When an sNIC fails, or its link to the ToR switch fails, if other links and the basic switching functionalities are still alive, the sNIC would turn into a passthrough device, forwarding NTs to other sNICs for processing.
When the entire sNIC fails, the endpoints connected to it will be disconnected to the rest of the data center.
This failure could be viewed as equivalent to traditional ToR switch failure but with a smaller failure domain (only the endpoints under the failed sNIC instead of the whole rack).
Data centers that desire stronger reliability [1]} could use a multi-homed solution by connecting each endpoint to two sNICs.
